3 hours in the background seems a lot to me.
I started the app clean and configured it from the start (it was a pain in the ass because I migrated my settings from Sync for Reddit lol) and the issue still remains, having this huge background usage prevents my phone from going to deep sleep properly which lends to a bigger battery drain.
EDIT: BTW the issue is gone when I set the app to restricted battery mode instead of optimized... But I'd rather keep it in optimized as it closes less often in the background, that is how I had it with Sync for Reddit, which on average its active background was several minutes only.
EDIT 2:
This is the process that Battery Guru/BBS says shows
job/io.syncapps.lemmy_sync/androidx.work.impl.background.systemjob.SystemJobService#9188
This is like someone standing in Times Square saying, "I don't go to New York or tourist destinations!"
Why are you here? How did you manage to get here?
Hurr durr, wank off on a bullshit forum for a bullshit app lol. Get a fucking life.